In the field of semiconductor device technology silicon nitride films may be utilized during the fabrication of semiconductor integrated circuitry. For example, silicon nitride films may be utilized as an insulating material during the fabrication of semiconductor device structures, such as, for example, transistors, memory cells, logic devices, memory arrays, etc.
There is a need in the field of semiconductor device technology for low temperature deposition processes for high quality silicon nitride films; such low temperature deposition processes should also provide precise control of the film thickness, thickness uniformity and conformality.
Common silicon nitride film deposition processes require high temperature deposition, i.e., around 600° C. to 800° C., to attain the reaction between precursors such as dichlorosilane (DCS) and ammonia (NH3). State of the art device structures may not be able to withstand such a high thermal budget which may further result in a deterioration of device performance and may cause device integration problems.
An alternative solution to high temperature deposition processes may be to utilize a plasma to activate the precursors which may in turn allow for low temperature reactions and reduced deposition temperatures for silicon nitride films. However, plasma based deposition processes may be limited in deposition performance, i.e., step coverage, uniformity of film quality achievable for high aspect ratio structures and plasma based deposition processes may damage the underlying device structures.
In some applications it may be desirable to form silicon nitride films only in certain areas of a substrate. Typically, such a result is achieved by depositing a continuous film and patterning it using subsequent lithography and etch steps. Such processing is time consuming and expensive, and does not offer the precision required for many applications. A possible solution is the use of selective deposition processes whereby the material is deposited only in the desired areas thereby eliminating the need for subsequent patterning steps.
Therefore low temperature selective deposition processes for silicon nitride films and semiconductor device structures including such selective silicon nitride films may be needed to improve semiconductor device performance.